Conventionally, a technique is known for adjusting the thickness or form of a rubber molded product discharged from a discharge opening to desired dimensions by inserting a die in the discharge opening of the extruder and changing the degree of insertion of the die into the discharge opening.
Meanwhile, for example, in a case of continuously manufacturing a rubber molded product in which two bands made of rubber are attached to both sides of a rubber sheet, it is necessary to continuously manufacture the two bands along with the sheet.
In such a case, when two discharge openings are provided in the extruder, the structure of the discharge openings becomes complicated and the number of the components in the extruder is increased, which is disadvantageous in terms of lowering the cost and achieving compactness of the extruder.
In addition, it is necessary to have a structure which is able to adjust the cross-sectional shape of each of the discharge openings from which rubber is discharged such that the bands have a predetermined shape and thickness. Providing this adjusting structure in each of the discharge openings further increases the number of components in the extruder.